IBM Support

IT26009: COLUMNAR ONLY: POSSIBLE WRONG RESULT IN EQUALITY JOIN WHEN COMPARING ZERO BINARY FLOATING POINT VALUE

Subscribe

You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • Prerequisites:
    - PowerPC platform
    - Equality join executed in Columnar Logic (under CTQ in the
    plan, for example)
    - Unary minus used on join predicate on a REAL or DOUBLE value
    and value is 0.0
    
    Sample:
    create table state(floatnr double, state varchar(20)) organize
    by column;
    insert into  state values(+0.0, 'CALIFORNIA');
    insert into  state values(+1.0, 'TEXAS');
    insert into  state values(+2.0, 'OREGON');
    insert into  state values(+3.0, 'FLORIDA');
    
    SELECT Y.FLOATNR, Y.STATE FROM STATE Y, STATE X WHERE X.FLOATNR
    = -Y.FLOATNR;
    
    FLOATNR                  STATE
    ------------------------ --------------------
    
      0 record(s) selected.
    
    Expected result:
    FLOATNR                  STATE
    ------------------------ --------------------
      +0.00000000000000E+000 CALIFORNIA
    
      1 record(s) selected.
    

Local fix

  • db2set DB2_CDE_HW_SIMD=13
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * ALL                                                          *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to Db2 11.1 Mod 4 Fixpack 4 or higher                *
    ****************************************************************
    

Problem conclusion

  • First fixed in Db2 11.1 Mod 4 Fixpack 4
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT26009

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    B10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2018-08-19

  • Closed date

    2018-11-27

  • Last modified date

    2018-11-27

  • APAR is sysrouted FROM one or more of the following:

  • APAR is sysrouted TO one or more of the following:

Fix information

  • Fixed component name

    DB2 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

  • RB10 PSN

       UP

[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSEPGG","label":"Db2 for Linux, UNIX and Windows"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Line of Business":{"code":"LOB10","label":"Data and AI"}}]

Document Information

Modified date:
07 May 2020